One of our developers reported that for the past week or two, the htdigest authentication that we have set up on our test sites in Apache is not working in IE10 on Windows 8. It's fine on IE10 on Windows 7, and it's fine on Chrome on Windows 8.

The specific behavior is: Navigate to site with htdigest authentication enabled, username and password form pops up, enter correct username and password, and the username and password box pops up again.

Potentially useful information:

• All patches applied on Windows 8 box
• No additional software on Windows 8 box other than Outlook 2013 and a browser test suite (Chrome, Firefox, Opera, Chrome Canary, Opera Next)
• Win8 running in a virtual machine on Xen
• Same behavior can be replicated on Win8/IE10 on Browserstack.com
• Server running Ubuntu 10.10 with Apache 2.2.16

This feels like a patch was applied to the Windows box that broke digest authentication for IE10 on Win8 (box configured for automatic updates). However, without knowing a specific date I can't necessarily nail this down. Has anyone else experienced this problem?

EDIT: This problem only happens in the "Metro" interface, not when running IE10 in desktop mode. As of a few weeks ago, it worked fine even in the "Metro" interface.